Form, fill and seal machines using printed top webs are well known. In some form, fill and seal machines, feeding of a bottom web pulls a printed top web bonded to the bottom web through a web printer, onto the bottom web and into a sealing station where the webs are heat and pressure bonded together to close filled pockets in the bottom web and form sealed packages.
Downstream feeding of the bottom web pulls the printed top web material from a supply roll, through the printer and onto the bottom web for heat and pressure bonding onto the bottom web. The high pulling force is transmitted from the bottom web to the top web through the previously formed and not yet cooled and stabilized heat and pressure bond between the webs. The pulling force stresses the bond and can rupture the bond securing the top web to the bottom web.
Form, fill and seal machines may be used to package sterile items such as pharmaceutical products, medical devices, foods and the like. A ruptured bond between the top and bottom webs due to the force required to pull the top web from the printer and onto the bottom web can destroy the sterility of the sealed pockets.
Higher speed form, fill and seal machines, the top web is fed between a pair of nip rolls located between the printer and the sealing station. The nip rolls are powered driven to pull the printed top web from the printer at a high speed and deliver the printed top web to the bottom web at the sealing station.
While the use of nip rolls to positively pull the top web from the printer for delivery to the sealing station increases throughput and reduces pulling stresses on the bond between the two webs, the nip roll engaging the top surface of the top web picks up wet ink from the top of the top web and reprints the ink on the top of the web, creating undesirable ghost images on the top web. Sealed packages with ghost images are not marketable.
Thus, there is a need for an improved web printing and feed machine which delivers printed top web to a form, fill and seal machine at low or no tension without stressing the bond between the top and bottom webs and does not print ghost images on the top web. The improved web printing and feed machine should feed top web through the machine and print the top web without increasing the tension of the top web when delivered to the form, fill and seal machine. The top web should not be fed onto the bottom web by pulling the top web through the printing and feed machine either by the bond with the bottom web or by nip rollers. The bottom web should not pull the top web through the printer and onto the bottom web. Rather, the top web should be paid out onto the bottom web under low or no tension without the use of nip rollers.